Bleaching montan wax



Patented Jan. 15, 1929.

UNITED STATES PATENT OFFICE.

WILHELI PUNGS, OF LUDWIGSHAFEN-ON-THE'RI-IINE, GERMANY, ASSIGNOR TO I.G.

FARBE'NINDUSTRIE AK'I'IENGESELLSCHAFT, OF FRANKFORT-ON-THE-MAIN, GER-MANY, A CORPORATION OF GERMANY.

BLEAGHING MONTAN WAX.

Ho Drawing. Application filed March 8, 1928, Serial No. 260,260, and inGermany March 11, 1927.

This invention relates to the bleaching of Montan wax.

A process is already known according to which Montan wax is bleachedwith chromic acid in glacial acetic acid. But glacial acetic acid hasmore the character of a solvent than of an acid, and it is thereforeoften difficult to initiate the reaction. On this account the process isvery dangerous, since on the further addition of chromic acid, after thedelay, the reaction usually begins very suddenly, in a violent,explosive manner.

I have now found that crude or deresinified Montan wax which areequivalents for the purposes of the present invention can besuccessfully bleached with chromic acid, it the operation be conductedin the presence of solutions of organic acids or sulfonic acids, thesebeing included in the expression organic acids, such as acetic acid,benzene sulfonic acid and the like. It has been found that the bleachingproceeds in a milder manner and more uniformly in such solutions than,for example, in mineral acid solutions, so that the wax substanceusually suffers no injurious chemical modification.

The following examples will further illustrate the nature of thisinvention but the invention is not restricted to these examples.

Ewample 1.

Earample 2.

150 kilograms of crude or deresinified Montan wax are finely distributedin 3500 litres of a solution of 45 parts by weight of benzolmonosulfonicacid in parts by weight of water, the mixture being stirred and heatedto about 100 C. A concentrated aqueous solution of 225 kilograms ofchromic acid is then slowly added, heating and stirring being continued.After from 2 to 3 hours a product is obtained which is as pale as thatpbtained by operating in sulfuric acid soluion.

The chromic acid in this example may be replaced by a correspondingamount of a chromate.

Eazample 3.

100 kilograms of deresinified Montan wax are heated with 400 kilo ams of50 per cent acetic acid to about 102 .,'whereupon a solution of 7 5kilograms of potassium bichromate or of 50 kilograms of chromic acid in750 litres of 50 per cent acetic acid is run in while stirring, thetemperature of themixture being maintained. The solution isbluish-greenin colour after about 1 hours. The stirrer is now stopped and thegreater part of the chromic salt solution drawn oil from under theMontan wax floating thereon after a short time. The mixture is thenagain heated to boiling and 7 50 litres of 50 per cent acetic acidcontaining 75 kilograms of potassium bichromate in solution are agalnadded. After about 2% hours, about three quarters of the spent chromiumsalt is drawn off. 450 litres of 50 per cent acetic acid containing 45kilograms of potassium bichromateare now added to the rest of thesolution containing the Montan wax.

The bleaching is completed by boiling for further three hours withstirring. In this way an excellent light coloured wax is obtained.

What I claim is:

1. A process for bleaching Montan wax,

which consists in treating the said wax with chromic acid in thepresence of solution of organic acids. a

2. A process for bleachingMontan wax, which consists in treating thesaid wax with chromic acid in the presence of aqueous solutions oforganic acids.

3. A process for bleaching Montan wax, which consists in treating thesaid wax with chromic acid in the presence of aqueous acetic acid.

4. A process for bleaching Montan wax, which consists in treating thesaid wax with an aqueous acetic acid solution of chromic acid at 102 C.

In testimony whereof I have hereunto set my hand.

WILHELM PUNGS.

